A conventional radiation treatment apparatus, in which a malignant tumor such as cancer is irradiated with radiation to annihilate the malignant tumor, is proposed. Some technologies for irradiating a tumor which has been displaced by patient's respiration (e.g. human lung cancer) with radiation by tracing the movement thereof are also introduced.
For example, Japanese Patent No. 3053389 discloses a moving body tracing/irradiating apparatus which traces the position of a dynamically displaced tumor by implanting a marker such as gold that a fluoroscope can detect near an in vivo tumor and performing image analysis by the variable density regulating cross-correlation method based on the images obtained by the fluoroscope and calculating the position of the marker (Patent Document 1). In this method, a dynamically displaced tumor in vivo is selectively irradiated with radiation to reduce the unnecessary radiation exposure to normal tissues.
Patent Document 1                Japanese Patent No. 3053389        